Ecological risk assessments for transgenic crops with combined insect‐resistance traits: the example of Bt11 × MIR604 maize

Abstract

Transgenic insect‐resistant crops produced by combining two or more insect‐control traits through conventional breeding are increasingly common in commercial cultivation. In some countries, cultivation of crops with combined insect‐control traits may require additional regulatory risk assessments, even though all component traits are approved for cultivation, which requires, among other things, a demonstration that cultivation of the crop poses negligible ecological risk; that is, there is a low probability of harm to non‐target organisms. In such situations, cultivation of a crop with the combined traits will also pose negligible ecological risk, provided two hypotheses hold: the potency of the proteins when combined is not greater than when separate; and the exposure of non‐target organisms to the proteins is not greater when the traits are combined than when they are separate. The ecological risk assessment for combined traits may be based on tests of these hypotheses, comprising tests for synergism between the proteins in species sensitive to the proteins, and comparisons of protein production in plants with the combined traits and plants with the separate component traits. Tests of these hypotheses are illustrated using Bt11 × MIR604 maize, which produces the insecticidal proteins Cry1Ab and mCry3A. Results from synergism studies using European corn borer and Colorado potato beetle, and from comparisons of the concentrations of Cry1Ab and mCry3A in Bt11 × MIR604, Event Bt11 and Event MIR604 maize, indicate that risks to non‐target organisms from the cultivation of Bt11 × MIR604 maize are no greater than from the cultivation of Event Bt11 or Event MIR604 maize.

A General Approach to Test for Interaction Among Mixtures of Insecticidal Proteins Which Target Different Orders of Insect Pests

“…A very similar approach was recently used to investigate the potential for interaction of a single lepidopteran-active protein with a single coleopteran-active protein (Raybould et al 2012). In this present work, for each combinatorial bioassay, a sensitive insect species (i.e., ECB to measure lepidopteran activity, and CPB to measure coleopteran activity) was exposed to the higher (∼LC 60 ) or the lower concentration (∼LC 30 ) of the insecticidal protein mixture alone, and in combination with the higher concentration of the other protein mixture for which it is insensitive (i.e., the insecticidal protein mixture that targets the other insect order).…”

“…The interaction studies can be a component of such assessments, along with other important environmental considerations specific to how the insecticidal protein traits are deployed (Raybould et al 2012). …”

Regulation of Agricultural Biotechnology: The United States and Canada

“…, there is no synergism between the insecticidal proteins, and the concentrations of the insecticidal proteins in the separate events are no greater than in the pyramid or stack (Raybould et al 2011b ) . , there is no synergism between the insecticidal proteins, and the concentrations of the insecticidal proteins in the separate events are no greater than in the pyramid or stack (Raybould et al 2011b ) .…”

Composition and rheological properties of flour and dough from genetically modified wheat (Triticum aestivum L.) Hi-Line 111

“…Agricultural genetic engineering has opened a new avenue in the development of genetically modified (GM) plants with enhanced insect or herbicide resistance, abiotic stress tolerance, or nutritional improvement (Sthrestha et al 2008;Raybould et al 2012). With the worldwide commercialization and rapid increase in genetically modified organisms (GMO), numerous transgenic crops are being developed with modified trait involving multiple genes for more and greater characteristics with the expectation of solving problem such as disease, weed management, enhancing production efficiency and improving functional properties (Shin et al 2013).…”